The present invention relates to a phase determination system.
Referring to FIG. 1, many electrical power distribution systems include a panel enclosure 10 into which is provided electrical power using one or more sets of wires 12. The electrical power may have any voltage, any current, and any number of phases (e.g., single phase, two phases, or three phases). Each phase of the electrical power to the power panel is normally provided to a separate bus bar 14a, 14b, and 14c, which are normally elongate conductors within the power panel 10. A plurality of circuit breakers 16a, 16b, 16c, etc., which trip or otherwise selectively disconnect electrical power, are electrically interconnected between one or more of the bus bars 14a, 14b, and 14c, and respective loads 18 external to the power panel 10. In many power panels 10 the circuit breakers 16 are vertically aligned in one or more strips 20 and 22. When the load 18 interconnected to a respective circuit breaker 16 within the power panel 10 draws excessive electrical current then the circuit break 16 trips or otherwise disconnects the electrical power to the load 18. In this manner, if a load shorts and thereafter draws excessive current then the circuit breaker will trip. Frequently, the load will be a three-phase load having three wires provided thereto, with one or more corresponding circuit breakers. For example, in many cases if one phase of a three phase circuit breaker trips, all three phases of the circuit breaker will disconnect power to the associated load.
In many business environments a set of electrical loads, such as motors, lighting, heating units, cooling units, machinery, etc., may be electrically interconnected to one or more circuits, each of which may be a single phase or multi-phase. Obtaining the total power usage of the business may be readily obtained by reading the power meter provided by the power utility. The power meter is normally electrically interconnected between the power panel and the power utility. In many circumstances, it is desirable to monitor the power consumption of individual loads or groups of loads. The use of power meters permits effective monitoring of the power consumption of particular loads. Also, a set of power meters permits effective sub-metering of different loads, buildings, or groups of loads to attribute and monitor the power usage of the business. For example, the power sub-metering may be used to attribute the power costs charged by the utility to different buildings, departments, or cost centers. The traditional approach to monitoring such power usage is to install a power meter at a location proximate the load itself. To install a typical power meter on a three phase load, a current sensor is located around each wire of the three phases and a voltage connection is electrically interconnected to each wire. Such a power meter is available from Veris Industries, LLC under the name H8035 Power Meter.